In order to realize advanced services, an effort has been made to impart detailed attribute information to individual data. On the other hand, an attempt to utilize a relationship between data in services has been studied (see Non Patent Literature 1). In particular, attention has been drawn to social relationships such as a relationship between people and a relationship between the context of movement of a person and location. The relationship of data is expressed as graph data in which data are represented by nodes and direct connection between data is represented by links.